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* doc/c-xtensa.texi (Xtensa Options, Absolute Literals Directive):

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Remove comments about placement of literal pools.
	(Literal Directive): Update description of literal placement.
	(Literal Prefix Directive): Remove statement that this does not apply
	to absolute-mode literals.  Describe new section naming scheme.
This commit is contained in:
Bob Wilson 2004-10-14 22:58:33 +00:00
parent 98b4dd9401
commit 40e7b7b9ef
2 changed files with 47 additions and 28 deletions
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8
gas/ChangeLog
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@ -1,3 +1,11 @@
2004-10-14 Bob Wilson <bob.wilson@acm.org>
* doc/c-xtensa.texi (Xtensa Options, Absolute Literals Directive):
Remove comments about placement of literal pools.
(Literal Directive): Update description of literal placement.
(Literal Prefix Directive): Remove statement that this does not apply
to absolute-mode literals. Describe new section naming scheme.
2004-10-12 Bob Wilson <bob.wilson@acm.org>
* config/tc-xtensa.c (xtensa_frequency_pseudo): Use set_subseg_freq.

67
gas/doc/c-xtensa.texi
View File

@ -54,9 +54,7 @@ Indicate to the assembler whether @code{L32R} instructions use absolute
or PC-relative addressing. If the processor includes the absolute
addressing option, the default is to use absolute @code{L32R}
relocations. Otherwise, only the PC-relative @code{L32R} relocations
can be used. Literals referenced with absolute @code{L32R} relocations
are always placed in the @code{.lit4} section, independent of the
placement of PC-relative literals.
can be used.
@item --target-align | --no-target-align
@kindex --target-align
@ -616,17 +614,17 @@ can be used to load a pointer to the symbol @code{sym} into register
the data in a literal pool.
Literal pools for absolute mode @code{L32R} instructions
(@pxref{Absolute Literals Directive}) are always placed in the
(@pxref{Absolute Literals Directive}) are placed in a seperate
@code{.lit4} section. By default literal pools for PC-relative mode
@code{L32R} instructions are placed in a separate section; however, when
using the @samp{--text-@-section-@-literals} option (@pxref{Xtensa
Options, ,Command Line Options}), the literal pools are placed in the
current section. These text section literal pools are created
automatically before @code{ENTRY} instructions and manually after
@samp{.literal_position} directives (@pxref{Literal Position Directive,
,literal_position}). If there are no preceding @code{ENTRY}
instructions, explicit @code{.literal_position} directives
must be used to place the text section literal pools; otherwise,
@code{L32R} instructions are placed in a separate @code{.literal}
section; however, when using the @samp{--text-@-section-@-literals}
option (@pxref{Xtensa Options, ,Command Line Options}), the literal
pools are placed in the current section. These text section literal
pools are created automatically before @code{ENTRY} instructions and
manually after @samp{.literal_position} directives (@pxref{Literal
Position Directive, ,literal_position}). If there are no preceding
@code{ENTRY} instructions, explicit @code{.literal_position} directives
must be used to place the text section literal pools; otherwise,
@command{@value{AS}} will report an error.
@node Literal Position Directive
@ -679,9 +677,6 @@ continue:
The @code{literal_prefix} directive allows you to specify different
sections to hold literals from different portions of an assembly file.
This directive only applies to literals referenced from PC-relative
@code{L32R} instructions; it has no effect for absolute literals
(@pxref{Absolute Literals Directive}).
With this directive, a single assembly file can be used to generate code
into multiple sections, including literals generated by the assembler.
@ -690,13 +685,34 @@ into multiple sections, including literals generated by the assembler.
.end literal_prefix
@end smallexample
For the code inside the delimited region, the assembler puts literals in
the section @code{@var{name}.literal}. If this section does not yet
exist, the assembler creates it. The @var{name} parameter is
optional. If @var{name} is not specified, the literal prefix is set to
the ``default'' for the file. This default is usually @code{.literal}
but can be changed with the @samp{--rename-section} command-line
argument.
By default the assembler places literal pools in sections separate from
the instructions, using the default literal section names of
@code{.literal} for PC-relative mode @code{L32R} instructions and
@code{.lit4} for absolute mode @code{L32R} instructions (@pxref{Absolute
Literals Directive}). The @code{literal_prefix} directive causes
different literal sections to be used for the code inside the delimited
region. The new literal sections are determined by including @var{name}
as a prefix to the default literal section names. If the @var{name}
argument is omitted, the literal sections revert to the defaults. This
directive has no effect when using the
@samp{--text-@-section-@-literals} option (@pxref{Xtensa Options,
,Command Line Options}).
Except for two special cases, the assembler determines the new literal
sections by simply prepending @var{name} to the default section names,
resulting in @code{@var{name}.literal} and @code{@var{name}.lit4}
sections. The @code{literal_prefix} directive is often used with the
name of the current text section as the prefix argument. To facilitate
this usage, the assembler uses special case rules when it recognizes
@var{name} as a text section name. First, if @var{name} ends with
@code{.text}, that suffix is not included in the literal section name.
For example, if @var{name} is @code{.iram0.text}, then the literal
sections will be @code{.iram0.literal} and @code{.iram0.lit4}. Second,
if @var{name} begins with @code{.gnu.linkonce.t.}, then the literal
section names are formed by replacing the @code{.t} substring with
@code{.literal} and @code{.lit4}. For example, if @var{name} is
@code{.gnu.linkonce.t.func}, the literal sections will be
@code{.gnu.linkonce.literal.func} and @code{.gnu.linkonce.lit4.func}.
@node Absolute Literals Directive
@subsection absolute-literals
@ -721,11 +737,6 @@ To change the @code{L32R} mode, the program must write the
to keep track of the mode and indicate to the assembler which mode is
used in each region of code.
Literals referenced with absolute @code{L32R} instructions are always
placed in the @code{.lit4} section. PC-relative literals may be placed
in the current text section or in a separate literal section, as
described elsewhere (@pxref{Literal Directive}).
If the Xtensa configuration includes the absolute @code{L32R} addressing
option, the default is to assume absolute @code{L32R} addressing unless
the @samp{--no-@-absolute-@-literals} command-line option is specified.